SDM660: ADSPRPC: Align the size of IOVA to 128MB

Align the size of the IOVA that is being passed
in the arm_iommu_create_mapping() to 128MB.

Change-Id: Ia554c2157d6c46b2f3848f993a7e61ff7f029547
Acked-by: Chenna Kesava Raju <chennak@qti.qualcomm.com>
Signed-off-by: Tharun Kumar Merugu <mtharu@codeaurora.org>